Source:NetHack 3.6.0/src/track.c

Below is the full text to track.c from the source code of NetHack 3.6.0. To link to a particular line, write [[Source:NetHack 3.6.0/src/track.c#line123]], for example.

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 /* NetHack 3.6	track.c	$NHDT-Date: 1432512769 2015/05/25 00:12:49 $  $NHDT-Branch: master $:$NHDT-Revision: 1.9 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 /* track.c - version 1.0.2 */
 
 #include "hack.h"
 
 #define UTSZ 50
 
 STATIC_VAR NEARDATA int utcnt, utpnt;
 STATIC_VAR NEARDATA coord utrack[UTSZ];
 

initrack

 void
 initrack()
 {
     utcnt = utpnt = 0;
 }
 

settrack

 /* add to track */
 void
 settrack()
 {
     if (utcnt < UTSZ)
         utcnt++;
     if (utpnt == UTSZ)
         utpnt = 0;
     utrack[utpnt].x = u.ux;
     utrack[utpnt].y = u.uy;
     utpnt++;
 }
 

gettrack

 coord *
 gettrack(x, y)
 register int x, y;
 {
     register int cnt, ndist;
     register coord *tc;
     cnt = utcnt;
     for (tc = &utrack[utpnt]; cnt--;) {
         if (tc == utrack)
             tc = &utrack[UTSZ - 1];
         else
             tc--;
         ndist = distmin(x, y, tc->x, tc->y);
 
         /* if far away, skip track entries til we're closer */
         if (ndist > 2) {
             ndist -= 2; /* be careful due to extra decrement at top of loop */
             cnt -= ndist;
             if (cnt <= 0)
                 return (coord *) 0; /* too far away, no matches possible */
             if (tc < &utrack[ndist])
                 tc += (UTSZ - ndist);
             else
                 tc -= ndist;
         } else if (ndist <= 1)
             return (ndist ? tc : 0);
     }
     return (coord *) 0;
 }
 
 /*track.c*/